1916663425721 has 24 divisors (see below), whose sum is σ = 2109547473600. Its totient is φ = 1740105972000.

The previous prime is 1916663425697. The next prime is 1916663425723. The reversal of 1916663425721 is 1275243666191.

It is not a de Polignac number, because 1916663425721 - 2¹⁸ = 1916663163577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1916663425723) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 379459646 + ... + 379464696.

It is an arithmetic number, because the mean of its divisors is an integer number (87897811400).

Almost surely, 2^{1916663425721} is an apocalyptic number.

1916663425721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1916663425721 is a deficient number, since it is larger than the sum of its proper divisors (192884047879).

1916663425721 is a wasteful number, since it uses less digits than its factorization.

1916663425721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8621 (or 8610 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 53.

The spelling of 1916663425721 in words is "one trillion, nine hundred sixteen billion, six hundred sixty-three million, four hundred twenty-five thousand, seven hundred twenty-one".